1. Field of the Invention
The subject invention relates to a laser guidance assembly for a lawn mower for navigating the lawn mower across a specified terrain.
2. Description of the Prior Art
Various laser-guided vehicles are well known in the prior art which utilize laser guidance systems to navigate across a terrain. The laser guidance assemblies usually include a first mirror supported by a mirror support, a diode for emitting a laser beam in a laser path to the first mirror for reflection by the first mirror in a generally horizontal direction to a course reflector, and a platform rotatably supporting the mirror support for rotation of the first mirror about a vertical axis. However, the first mirror is held at a fixed angle relative to the platform and is unable to scan in a vertical plane to locate the course reflectors as the lawn mower traverses uneven terrain.
One guidance system, shown in U.S. Pat. No. 5,426,584 included mounting the guidance system between a plurality of gimbaled brackets which would allow the laser beam to be scanned vertically without changing the angle of the mirror. As the lawn mower traversed uneven terrain, the entire assembly would shift to remain normal with gravity. The shifting is very erratic and unsteady. A drive was added to control the shifting of the assembly and the gimbaled brackets. However, the mounting of the guidance system between the brackets does not allow precise movement of the first mirror angle to precisely locate the course reflectors. The inaccurate measurement of the location of the course reflectors will produce an incorrect position for the lawn mower.
The invention provides a laser guidance assembly for a vehicle. The assembly includes a platform supported by the vehicle and a mirror support rotatably supported by the platform and being rotatable about a vertical axis relative to the platform. A first mirror is supported by the mirror support rotatable about the vertical axis. A diode emits a laser beam in a laser path to the first mirror for reflection by the first mirror in a generally horizontal direction. The laser guidance assembly is characterized by having a pivotal connection between the first mirror and the mirror support for allowing oscillation of the first mirror about a horizontal axis relative to and independent of the platform and the mirror support.
The invention provides a laser guidance assembly for a lawn mower including a first mirror, a diode for emitting a laser beam in a laser path to the first mirror for reflection by the first mirror in a generally horizontal direction, a mirror support supporting the first mirror, a course reflector for directing a reflected laser beam back to the first mirror, and a platform rotatably supporting the mirror support for rotation of the first mirror about a vertical axis. The laser guidance assembly is characterized by having a pivotal connection between the first mirror and the mirror support for allowing oscillation of the first mirror about a horizontal axis relative to the diode during rotation of the mirror support about the vertical axis.
The pivotal connection allows the angle of the first mirror to be precisely controlled for locating the course reflector. The determination of the precise location of the course reflector allows the lawn mower to be operated with much tighter tolerances which allow the lawn mower to be more accurate.